Federal investigators have begun looking into closed-door negotiations between the Bush administration and Plum Creek Timber Co., the nation's largest owner of private land.

Disturbed that negotiations about U.S. Forest Service road easements near Plum Creek lands in Montana took place privately, Sen. Jon Tester, D-Mont., last month asked the Government Accountability Office to investigate both the private nature of those talks and their outcome.

Democratic presidential candidate Barack Obama criticized the talks soon after he spent the Fourth of July in Montana.

Agriculture Undersecretary Mark Rey, who oversees the Forest Service, confirmed Wednesday that the GAO contacted his office.

"We met with them (investigators) once, and I expect we will meet again," Rey said in a phone interview. "They asked for information, which we provided and will continue to provide."

He said the GAO indicated it may report its findings in a couple of months.

Plum Creek was "proactive" and sent the GAO a letter "offering to work with them in any way we can," said Rick Holley, chief executive of Plum Creek, which owns 8 million acres in the United States. The largest holdings, 1.2 million acres, are in Montana.

It was over a span of about 18 months that representatives of Seattle-based Plum Creek and Rey's staff privately negotiated changes to an agreement on company use of Forest Service roads, Holley told The Associated Press during a Wednesday interview in Helena. Rey said the amendments likely will be formalized in July, but he did not offer a specific date.

Some county commissioners in Montana say the amendments will make it easier for Plum Creek to sell timberland for houses or other development, boosting the cost of providing county services such as fire protection in outlying areas. Sportsmen, generally welcome on Plum Creek lands, worry about loss of places to hunt if houses replace woodlands.

"Quite frankly, we were very surprised this became the issue it became," Holley said.

The executive said, as Rey did earlier, that Plum Creek has long had use of Forest Service roads to access its lands for any purpose. That is a claim challenged by Missoula County officials, who say the easements allow road use only for forest management and logging.

Holley said the amendments do not change purposes for which the roads may be used, but do add provisions.

One demands that future buyers of Plum Creek lands take measures to reduce wildfire risk on their parcels, he said, and another spells out buyers' responsibility for sharing the cost of maintaining federal logging roads used for access.

The easement agreement dates to the 1960s, Holley said. Plum Creek approached federal officials about it after a Forest Service ranger in Seeley Lake indicated to a buyer of company land in 2006 that there were issues involving use of federal roads for land access by the buyer, he said.

Holley expressed some regret about the closed-door nature of the negotiations, saying that "perhaps we should have at least gone to them (Missoula County officials) and said, 'What do you guys think?"'

In the last five years, Plum Creek has sold 210,000 acres in Montana, 180,000 of them either to conservation buyers or Stimson Lumber Co., Holley said. Of the remainder, 27,000 acres were for homesites or recreational use and 3,000 acres were sold directly for development, he said. Apart from a recent 320,000-acre conservation deal announced by Montana Sen. Max Baucus, the company, The Nature Conservancy and The Trust for Public Land, Holley said he does not expect Plum Creek's Montana land sales over the next five years to surpass those of the previous five.

In a phone interview Wednesday, Tester said many questions about the easement negotiations remain and he is eager to get the GAO report.

"I think it's great that Plum Creek is being proactive with the GAO," Tester said. "It's important that the Forest Service is proactive, as well."